Syncthing
Peer-to-peer file sync with no central servers, end-to-end encryption, and automatic LAN discovery. Free and open source. Runs on any hardware
Quick Start
docker run -p 8384:8384 -p 22000:22000/tcp -p 22000:22000/udp syncthing/syncthing Overview
Syncthing is for people who want file sync without handing the files to Dropbox, Apple, Google, or anyone else. Your devices decide what connects. Your files stay on your machines.
Under the hood, Syncthing works peer to peer. Each device gets a unique cryptographic identity, and connections are authenticated and encrypted using TLS with perfect forward secrecy. On a local network, devices discover each other automatically with no configuration. When devices are on different networks, Syncthing uses relay servers to broker the initial connection, but your actual file data still travels directly between your devices, not through any third party.
Getting it running is fairly painless. Install the Go binary (or pull the Docker image), open the browser UI on port 8384, share a Device ID with another machine, and choose which folders to sync. No account to create, no cloud dashboard.
There are a couple of catches. Syncthing is not a backup. If you delete a file on one device, that deletion syncs to all connected devices. Enable file versioning on your most important folders. The other catch is that both devices need to be online at the same time for sync to happen. If you work on a laptop away from home, your desktop will not receive changes until both are connected. Running it on a NAS or always-on server mostly removes that problem.
The official Android app was discontinued in December 2024. Syncthing-Fork on F-Droid is the actively maintained community replacement and works identically.
Syncthing: Pros & Cons
| Pros (The Wins) | Cons (The Friction) |
|---|---|
| Privacy: True P2P with no third-party servers; data never leaves your devices. | Simultaneity: Both devices must be online to sync; a NAS relay mostly removes this. |
| Security: TLS with perfect forward secrecy; cryptographic device identity. | Not a backup: Deletions propagate everywhere; enable versioning to protect yourself. |
| Performance: Block-level sync and LAN discovery; fast on local networks. | No link sharing: Recipients need Syncthing installed; no guest download links. |
| Lightweight: Single Go binary, low resource use, runs on a Raspberry Pi. | Android: Official app discontinued Dec 2024; use Syncthing-Fork from F-Droid. |
Use Cases
Specific ways to use Syncthing for your workflow.
Deployment Strategy
Recommended ways to host Syncthing in your own environment.